Adjustable resistence unit.



B. A. LUNDY. ADJUSTABLE RESISTENC'E UNIT.

APPLICATION FILED mmzs. 191B.

Patented Aug. 20, 1918.

F 4 I INVENTOR I '15 Rem/j 11%.

BY Qsw$ A TTOHNE Y i a specification.

BEVERLY A. LUNDY,1OF ALBANY, N EW YORK. ASSIGNORT0.EHALLSWITCH.fiaSIGIQL 00., ACORPORATION 0F MAINE.

ADJUSTABLE uni'ig.

()ne object is to provide a resistance unit whereby the resistance of a circuit may be changed without interrupting the flowof current in the circuit.

Another object is to provide a resistance unit'which is non-inductive and adjustable.

. i A further objectis to provide a unit which maybe easily adjusted with the maximum fineness of adjustment."

A futher object is to provide a unit which has a fixed non-adjustable resistance and an adjustable resistance so that the resistance may not be reduced below a certain point.

Still further objects and advantages of the invention willbe apparent from the accompanying description and the appended claims.

Figure 1 shows a plan of plete.

Fig. 2 is a longitudinal section through the unit showing the electrical connections, the means of clamping the unitto its base the unit comand also the means of, adjustment of the same. Fig. 3 shows the resistance coll independent of the unit in order to show the form of the non-inductive winding.

Fig. 4 is a plan view of Fig. 3.

Fig. 5 is the plan of a modified form of adjusting ollar.

Referring to Figs. 1 and 2 I have shown at l a base which may be made of any suitable insulating. material. The base 1 is provided with a recess 2 on the under side thereof and an opening 3 which passes through the base and terminates in a raised y boss, 4. The base is further supplied with screw holes 5 and 6 and is adapted to carry at either end binding posts 7 and 8 for the purpose of connecting the resistance unit into any. electrical circuit. An upright member 9 of suitable insulating material is provided with an enlarged lower part 10 and a suitable spacing thread 11 around its outer circumference. A wire 12 of suitable Application filed Januar 29, 1918. Serial No. 214368;

Specificatibn of hetters han. Aug- 2 0, 1918.

resistance material is provided which passes from binding post 7 through the enlarged part 10 and is wound in such a Way as to lay in the'threads 11 formed on the upright n'ien'iber 9, passing around this'memberin the thread to the top of the member, pass-f iiig across the member 9 at the top in a slot- 13 provided therefor and passing around a parallel thread to the bottom ofthe mejrn-f ber and connecting to the terminal- 8.

By referring to Figs; 3 and' l'it will be seen that the wire 12will lay in parallel concentric windings passing from the terminal7 around w'indingsto thetop ofthe member 9 and thence *backaround parallel windings tothe terminal 8,'t he parallel windings thereby serving to counteract their respective self inductions, thereby making, 3 the resistancenon-inductive. The upright" member 9' with its windings 12 is passed through the opening 3 in the base 1. "A

clamping nut 14 made of suitable insulat ing'material is provided with a thread '15 ,adapted to engage theouter periphery of;

the windings 12 in such a manner that when; the clamping nut 14 is screwed down overv the windings 12, it will clamp the Upright,

member 9 with its winding, in theposition shown. The member 14 will also serve to seal a portion of the winding 12 in the opening 3 of the base 1. The splitnut 16 made of suitable conducting material isalso.

provided with the thread 17 adapted toen-v gage the winding 12, this nut being splitat 18 in order that it may spring together to tightly clamp about the wire 12. From the above it will be seen that normally a circuit will pass from binding post 7 through wire 12 up one spiral of the windinguon mem-- her 9 and down the other spiral of the wind ing to binding post 8. However, when nut. 16 is threaded over the winding 12,.it will serve to short circuit a corresponding number of turns in accordance with the distance which it is threaded down'over the winding and it will -be"apparent that by, rotating the nut 16 thereby screwing it up and down overthe surfaceof winding 12, that more or less turns of the winding will be shunted out by the nut thereby varying the total resistance of the circuit between binding posts 7 and 8.

Referring to Fig. 5 I have shown a modified form of split nut which is cut away at 19 leaving small contact surfaces at 20 which are provided with threads 21. It will be seen that with this form of nut a greater contact pressure may be obtained per unit of area on the outside periphery of wire 12 than with a solid nut.

While I have shown and described one specificform and mode 'of construction of: my'device, it is obvious that various forms of construction may parting from the spirit of the invention.

What I claim is 1. A resistance unit comprising a base of insulating material, a threaded upright member adapted to pass through said base and be supported by same, resistance wire wound coincident with the threads on said threaded member, a cavity formed in the base for inclosin a portion of said resistance wire, a col ar of insulating material threaded over said resistance wire to lock the upright member in place and seal the inclosed portion of said resistance wire, and,

a collar threaded over said resistancewire and adapted to make electrical contact with the resistance winding and adapted to be r0- tated about the winding to adj list the resistance of the same.

2. In a resistance unit, a non-inductive helical resist-ance winding, and a collar of conductive material threaded over said helical winding and adapted to shunt turns of Y said winding to adjust the resistance of the same.

3. In a resistance unit, a helical resist-ance winding, and a collar threaded over said helical winding and adapted to make electrical contact with more than -one turn of same, and means for rotating said collar about the winding to adjust the resistance of j e same.

i 4. In a resistance unit, a non-inductive helical resistance winding, a collar threaded over said helical winding and adapted to make electrical contact with more than one turn of same, and means for rotating said collar about the winding to adjust the resistance of the same.

be used without de- 7 In a resistance unit, a helical resistance winding, a portion of said winding being of non-adjustable fixed resistance, a collar threaded over said helical-winding adapted to make electrical contact with more thanwinding to "adjust the resistance of the same.

9. A resistance unit comprising a base of insulating material, a threaded upright member of insulating material removably mounted in said base, a resistance wire wound coincident with the threads on said threaded member, and a collar of conductive material threaded over said resistance wire and adapted to shunt turns of said resistance wire to adjust the resistance of the same.

10. A resistance unit comprising a base of insulating material, a double pitch threaded upright member of insulating material supported by said base, resistance wire wound coincident with the threads on said threaded member, and a collar of conductive material threaded over said resistance wire and adapted to shunt turns of said resistance wire to adjust the resistance of the same.

11. A resistance unit comprising a base of insulating material, a threaded upright member of insulating material supported by said base, a resistance wire wound coincident with the threads on said threaded member, means for permanently inclosing a fixed portion of said resistance wire, a collar threaded over said resistance wire and adapted to make electrical contact with more than one turn of same, and means for rotating said collar about the winding to adjust the resistance of the same.

12. A resistance unit comprising a base of insulating material, a double pitch threaded upright member of insulating material supported by said base, resistance wire wound coincident with the threads on said threaded member, means for inclosing a portion of said resistance wire, a collar threaded over said resistance wire and adapted to make electrical contact with more than one turn of same, and means for rotating said collar about the winding to adjust the resistance of the same.

In testimony whereof, I have signed my name to this specification.

BEVERLY A. LUNDY.

copies of this patent may be obtained for five cents each, by addressing the Commissioner or l'stsnts, Wsshingtal, 13.0." 

